Content-type: text/html Man page of su

su

Section: User Commands (1)
Index Return to Main Contents
 

NAME

su - Substitutes user ID temporarily  

SYNOPSIS

su [-|-f] [user] [shell_option] [shell_command]


 

OPTIONS

Prevents the user's shell initialization file from being executed by passing the -f option to the user's shell, thus making su start up faster. The -f option is supported by the csh family of shells. Simulates a full login by executing the commands in either the .cshrc and .login files for csh or the .profile file for sh and ksh and by setting the current working directory to the user's home directory. Passes the specified shell option flag to the newly invoked user's shell for execution. The shell_option must be supported by the invoked shell. The csh, sh, ksh, and any other interactive command shell support the commonly used -c shell option. By default (no ``shell_option''), the shell is opened with the -i (interactive) shell option. See the reference page for the shell you are using for more information on the shell options. Passes the specified command to the newly invoked user's shell for execution. The shell_command must be supported by the invoked shell.
 

DESCRIPTION

The su command demands the password of the specified user, and if it is given, changes to that user and invokes the user's shell without changing the current directory.

Except in a case where the - option is used, the user environment is unchanged except for HOME, SHELL, USER, and LOGNAME which are taken from the password file for the user being substituted (see environ). The new user ID stays in force until the shell exits.

If no user is specified, root is assumed. Only users who belong to group number 0 (system) can issue su to become root, even with the root password. To remind superusers of their responsibilities, the shell substitutes a # (number sign) for its usual prompt.

Shell commands may be passed to the shell that is spawned by su by including them on the command line after the su flags and arguments. After the flags recognized by su and the user argument are processed, unrecognized command line flags (shell_options) and/or arguments (shell_commands) are passed to the shell for execution. If the spawned shell does not support the command or the format of the command, the command is not executed and the resulting shell behavior and error messages are determined by the shell.
 

Security Restrictions

The su command fails if any lock conditions exist on the target account. Specifically, if the destination account was retired, if the number of unsuccessful login attempts exceeds the maximum allowed, if the administrative lock was applied, or the password's lifetime was exceeded, the Information System Security Officer (ISSO) must unlock the destination account before any user can log in to it or use su to transition to it.
 

SECURITY NOTE

This security-sensitive command uses SIA (Security Integration Architecture) as an interface to the security mechanism(s) that perform the actual user validation. See the matrix.conf(4) reference page for more information.
 

SEE ALSO

Commands:  csh(1), ksh(1), sh(1)


 

Index

NAME
SYNOPSIS
OPTIONS
DESCRIPTION
Security Restrictions
SECURITY NOTE
SEE ALSO

This document was created by man2html, using the manual pages.
Time: 02:42:45 GMT, October 02, 2010